Process of making camphor.



UNITED STATES Patented September 27, 1904.

PATENT OFFICE.

KARL STEPHAN AND PAUL HUNSALZ, OF BERLIN, GERMANY, ASSIGNORS TO CHEMISCHE FABRIK AUF LIN, GERMANY.

ACTIEN, (VORM. -E. SCHERING,) F BER- PHOCESS OF MAKING CAMPHOR.

SPECIFICATION forming part of Letters Patent No. 770,940, dated September 27, 1904. Application filed April'29, 19.0.4:- Serial No. 205,604. (Specimens) To all whom it may concern.-

Be it known that we, KARL STEPHAN and PAUL HUNSALZ, both chemists and doctors of philosophy; and residing at Berlin, Germany,

have invented a new and useful Improvement in Processes of Manufacturing Camplior from Isoborneol, of which the following is a specification.

Hitherto camphor has only been manufac- I0 tured from isoborneol by means of acid oxidizing agents, such as chromic acid and nitric acid. Further, also, it has been proposed to use permanganate in glacial acetic acid, (see Berta/ate der Denise/Len Chemise/ten Ge- I5 sellschaft, XXXIII, page 3430,) and it is there stated that isoborneol is transformed quantitatively into camph'or. This statement,

however, is untrue, as at the most ten per cent. of camphor is formed. We have now 2 discovered that a very high yield-from ninety-five to one hundred per cent.is obtained when isoborneol (whether as a fine powder or dissolved in a solvent which is unaffected by oxidizing agents, such as benzene 5 (OGHG) or petroleum-ether) is oxidized by means of an aqueous solution of a permanganate. The oxidation takes place, therefore, not in an acid, but in an alkaline solution. The alkaline reaction may be reduced to a 3 neutral one without altering the result of the process. Apart from the high yield obtained by this process it has also the advantage that a camphor of great purity is obtained, and the formation of by-products, as are inevitably formed, by treating isoborneol with chromic acid and nitric acid, is wholly avoided.

Example: Ten kilos of isoborneol either finely powdered or dissolved in ten kilos of benzene (OGHG) are well stirred with a solution of ten kilos of potassium permanganate in one cubic meter of water at the ordinary temperature until the color of the permanganate has vanished. The mixture is distilled with steam and the resulting product crystallized from a solution in petroleum-ether, whereby the camphor is obtained in a pure state. In place of using a one-per-cent. aqueous solution a concentrated permanganate solution may of course also be gradually added, care being taken that the concentration in the oxidizing vessel does not rise much above one per cent. By using petroleum-ether as a solvent or by using another permanganate the reaction proceeds in the same way.

We claim as our invention The process of manufacturing camphor from isoborneol, which consists in causing watery solutions of permanganate to react upon isoborneol, and isolating the camphor thus formed, substantially as described.

In testimony whereof we have signed our names to this specification in the presence of two subscribing witnesses.

, KARL STEPHAN. PAUL HUNSALZ. Witnesses:

HENRY HASPER, WOLDEMAR HAUPT. 

